The Bombardier Dash 8 Q400 is a small twin-engine turboprop used by regional airlines for flights of 500 miles or less. The Canadian plane is popular for its low operating costs. The props fly almost as fast as jets -- its cruising speed is 414 miles per hour -- but it uses significantly less fuel.

Scandinavian Airlines abandoned its fleet of 27 Dash 8 Q400s in October 2007 after three such planes that it operated crashed that year because of faulty landing gear.

Mats Jansson, Scandinavian's chief executive, said at the time that confidence in the plane had diminished considerably "and our customers are becoming increasingly doubtful about flying in this type of aircraft."

John Dueholm, Scandinavian's deputy chief executive, also said then: "There is a risk that use of the Dash 8 Q400 could eventually damage the SAS [Scandinavian] brand."

Despite the issues in Scandinavia, airlines have been shifting toward the 74-seat Q400 because of its significant fuel savings; the plane uses roughly 30 percent less fuel than a jet of similar size.

Continental Airlines and its regional partner Colgan Air, which operated the downed aircraft, announced in March that they would start flying 15 of these turboprops for short flights out of Newark airport.

Montreal-based Bombardier is the world's third largest maker of civil aircraft and biggest maker of rail equipment, including New York City subway cars. The company's stock fell about 3.5 percent in the first few minutes of trading on the Toronto Stock Exchange.

"Until such time as the investigators release any information or findings, Bombardier cannot comment further or speculate on the cause of this accident," the company said in a statement this morning.

Colgan Air was founded in 1965 and is is a regional airline that flies under the flags of Continental Airlines, United Airlines and US Airways, serving more than 65 cities in 15 states.

It operates Continental Connection flights from Newark and Continental's other major hub in Houston. As US Airways Express, Colgan Air serves more than 35 cities in the eastern US from hubs in Boston, New York, Pittsburgh and Washington, DC. In Washington, it also operates flights as United Express.

Members of the founding Colgan family sold the carrier to Pinnacle Airlines Corp. for $20 million in 2007, according to Hoovers. Pinnacle's stock is down more than 20 percent today.

Possible Ice Problems

The Q400 had its first flight in 1998 and entered commercial service in February 2000. The Colgan Air plane that crashed Thursday on its trip from Newark Liberty International Airport in New Jersey to Buffalo Niagara International Airport was manufactured in 2008 and was certified to fly April 16.

In recorded conversations heard after the Continental flight went missing, pilots in other planes in the Buffalo area could be heard discussing ice build-up on their aircrafts' wings.

"We've been picking up ice here for about the past 10 minutes," one pilot said.

John Nance, an aviation expert and ABC News consultant, talked about how props handle ice storms.

"Well, rime ice or little super-cooled droplets are water that end up [forming] ice when you hit them and usually rime ice is something this type of aircraft can handle very well," Nance said on "Good Morning America" today. "What we worry about is a type called clear icing but there wasn't any indication of that."

"The thing is, it's very seductive at that point to think that maybe icing was part of the problem, but this airplane can handle that so well and it's a brand new airplane," he said. "I really caution that it's probably going to be something more than this and maybe something completely dissimilar."

Colgan Air confirmed Monday it had agreed to buy another 15 Q400 turboprops from Bombardier in addition to the 15 announced in January. Colgan Air operates a fleet of 56 turboprop aircraft: 15 Bombardier Q400, 40 Saab340 and one Beech 1900.

Other airlines have also been shifting toward the Q400.

In the last few years, Horizon Air, a subsidiary of Alaska Airlines, has moved away from its fleet of 20 CRJ-700 regional jets as part of a plan to only fly Q400s.

Upstart airline Porter exclusively flies the Q400. The airline only flies short-hop trips from Toronto's City Centre Airport to destinations including Newark, Montreal, Chicago and Ottawa.

Porter calls the Q400 "the most technologically advanced regional aircraft in the world," saying it is fast and quiet.

Airlines overseas have also been making the switch to the Q400. Air New Zealand, Philippine Airlines and Portugal's Air Acores have all placed orders for the turboprop.

The Q400 is based on the old de Havilland range of Dash aircraft. Manufacturer Bombardier calls it "the most technologically advanced turboprop airliner." It touts the cheap operating costs of the Q400 and said it is "among the lowest of any regional aircraft."